In order to protect a wafer during semiconductor manufacturing process, the wafer is deposited in a wafer cassette for storing or transporting.
The wafer is conventionally deposited in an accommodation groove of the wafer cassette, and it can be loaded and unloaded in vertical or horizontal way. But no matter in which way, it is not easy for the operator or robotic arm to take the wafer.
In terms of vertical way, the wafer has to be taken in vertical way because the wafer is deposited upright in the accommodation groove, otherwise the wafer is prone to touch the adjacent wafer and crack during taking the wafer. And improper taking will cause the wafer to fall down and break while loading or unloading.
In terms of horizontal way, the wafer is deposited in the accommodation groove horizontally, so the wafer will be rubbed against the wafer cassette while drawing out. Likewise, the improper taking also will cause the wafer to fall down and break.